Brandon, Florida -- A teenager was seriously hurt after her car drove off an exit ramp and plunged into a retention pond Monday morning.

The Florida Highway Patrol report says around 10:18 a.m. 17-year-old Natasha Thompson was driving her Infinity sedan down the I-75 exit ramp leading to the Lee Roy Selmon Expressway when, for some unknown reason, she drove off the road's north shoulder.

The car fell 50 feet and landed upside down in a retention pond.

Nearby highway and bridge construction workers with CTEC and Associates saw the crash and ran to the scene. 56-year-old Terry Stiles of Madeira Beach jumped in to rescue Thompson and reportedly performed CPR after pulling her to shore.

Thompson was taken to Tampa General Hospital where she remains in critical condition.